Currently, a variety of different clutch systems are used for various vehicles, such as ATV's, including roller clutch systems. Many of these clutch systems employ a dog clutch or splined collar arrangement that can be engaged by pulling a lever. Additionally, there are some electronically-actuated clutch systems that have been recently developed, as well.
These roller clutch systems are typically packaged in their own housings and bolted to the front transmission output flanges. The inner race is typically splined to the male output shaft from the transmission, whereas the clutch outer race has a female spline that is adapted to the front drive shaft. For example, certain roller clutch systems employ a roller clutch in a separate housing bolted to the front differential housing. In most of these systems, the input comes from the front driveshaft, and is connected to the roller clutch outer race. The clutch inner race is splined onto the front differential's pinion shaft.
One disadvantage with conventional roller clutch systems is that the dog clutch can be damaged during engagement while the vehicle is moving, as well as being complex and expensive to design and manufacture. Additionally, because separate housings are employed for the differential and clutch units, separate seals are needed on the input and output portions, and the clutch unit is required to be pre-greased before final assembly. Furthermore, ball bearings and a needle roller bearing are generally required to position the parts relative to each other and within the clutch housing. Also, the coil wire must be fed through the outer wall at the back end of the clutch housing during installation of the coil, a process that is quite time-consuming and difficult.
Therefore, there exists a need for new and improved clutch systems, especially those operable to provide control of the transmission of torque to the front (or rear) wheels, thus being operable to change the vehicle from a two-wheel, rear-drive (or front-drive) vehicle to a four wheel drive vehicle by engaging the clutch systems thereof.